I have Neuron successful installed on OSX and Windows 7/10... but I have failed with two separate linux (Ubuntu) machines now and so I think it is time to call for help. I don't have much experience with linux, so it is highly probably I am being an idiot. I have been trying off and on for days, though and read through similar sounding issues. I have the exact same error on both of the Ubuntu systems I tried, so it looks like I am doing something systematically wrong rather than this being due to a bug.
What I did:
Installed Anaconda as ever (3: Python 3.7, Ipython 7.4). I use Spyder.
Hello World is fine.
Downloaded the latest (7.6) neuron debian pre-built binary and accepted all the defaults.
Added the .../lib/python folder to the PYTHONPATH in Spyder.
Checked/added that nrn..../bin is in the PATH.
Then from Spyder.. from neuron import h, gui, rxd results in the hoc37 error of this title.
within the PYTHONPATH there is no hoc37.
Please can you help me diagnose and fix this?
Thank you
Richard

Thank you for your reply,
So firstly, no NEURON does not work from a regular python prompt. In fact it gets less far, failing to find neuron at all, because I only set PYTHONPATH within the PYTHONPATH preferences of Spyder. Same as I do on my mac.
Secondly, the PYTHONPATH I am using on these UBUNTU systems is /usr/local/nrn/lib/python
I didn't know there was an alternative. I will try that!
...tried the alternative path ( /usr/local/nrn/share....) and get exactly the same error as with the other path.
If no PYTHONPATH is set it cannot find the "neuron" package. If PYTHONPATH is set, apparently correctly, it cannot find "hoc37".

BW
Richard
ps...so I also tried Python 35 and 36 and got, of course cannot find hoc35 and hoc36 respectively with those...

If so, and this is in your PYTHONPATH, then launch
python3 -v
import neuron

This last will be very voluminous, but what is desired is a an error message that will hint as to what went wrong. In my case (nothing is crashingly wrong) it loaded
# extension module 'neuron.hoc' executed from '/usr/local/nrn/lib/python/neuron/hoc.cpython-37m-x86_64-linux-gnu.so'
and after another thousand lines or so ended up with
# wrote '/usr/local/nrn/lib/python/neuron/__pycache__/psection.cpython-37.pyc'
import 'neuron.psection' # <_frozen_importlib_external.SourceFileLoader object at 0x562e7d6213c8>
import 'neuron' # <_frozen_importlib_external.SourceFileLoader object at 0x562e7c9f23e8>
>>>
>>> neuron.__version__
'7.6.6'
>>>

I was surprised that there did not seem to be an explicit attempt during import to load the file
hoc.cpython-37m-x86_64-linux-gnu.so
I would be curious what happens if you temporarily
cp hoc.cpython-37m-x86_64-linux-gnu.so hoc.so # be sure to make a copy of hoc.so first!!!
cp hoc.cpython-37m-x86_64-linux-gnu.so hoc37.so
and try again.
I'm also wondering about why the second try 'import neuron.hoc' raised
ImportError: libreadline.so.5: cannot open shared object file: No such file or directory

Can you show the output of
ldd /usr/local/nrn/lib/python/neuron/hoc.cpython-37m-x86_64-linux-gnu.so

In my hands one of the output lines is
libreadline.so.5 => /lib/x86_64-linux-gnu/libreadline.so.5 (0x00007fb9bbac0000)

What libreadline exists in your /lib/x86_64-linux-gnu
I have libreadline versions for 5, 6, 7
You might be able to fix with
sudo apt install libreadline5
It that fixes your issue i need to ponder why the neuron install of the deb file did not automatically download and install the correct readline.
(0f course all this assumes i am not barking up the wrong tree.)

On my machine I see the line
libpython3.7m.so.1.0 => /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0 (0x00007f1afd160000)
Anyway, is there a file of that name within your anaconda installation.
In the old days we'd start thinking in terms of LD_LIBRARY_PATH but I think the right approach nowadays is to run ldconfig

I think we are close in the sense that things will work if the system can find all the referenced shared libraries that are explicitly listed with
ldd

Although my default python3 comes from python.org, I also have anaconda3 (python3.7) installed and I see that the library you need is in
/where/you/installed/anaconda3/lib
So try
export LD_LIBRARY_PATH=/where/you/installed/anaconda3/lib
and see if things launch correctly.